Offloading location computation from cloud to access point (AP) with projection on base phase vectors

ABSTRACT

Offloading of location computation from a location server to an access point through the use of projections on base phase vectors may be provided. First, an Access Point (AP) may receive a set of two or more base phase vectors from a location server. Next, the AP may measure a measured phase vector for a first signal from a user device. Then, the AP can determine projection values based on a comparison of the measured phase vector to each base phase vector. From these comparisons, the AP can determine a subset of base phase vectors with the highest projection values. The AP can then send the projection values and the subset of base phase vectors to the location server, wherein the location server determines the device location from these projection values and subset of base phase vectors.

TECHNICAL FIELD

The present disclosure relates generally to location services in acomputer network.

BACKGROUND

A computer network or data network can interface with devices thataccess the network to receive various services. Some of the servicesrequire location information about the device. For example, some ofthese services may include advertising goods or services located nearthe device, providing information about another object (e.g., a paintingor sculpture in a museum, a location on a battlefield, etc.) near thedevice, etc. Generally, the location computations are concentrated on acentral server in communication with the Access Points (APs) thatinterface with the devices.

One method for determining location of a device is for a Time Of Arrival(TOA) antenna information associated with a device to be sent to acentral server. Then, several different sets of antenna information,from several APs, can be combined to locate (for example, throughtriangulation) the device. Current location (also referred to ashyperlocation) requires a group of APs to each measure an AoA(Angle-of-Arrival) phase vector for a specific client and send all theseAoA phase vectors to a central location server or cloud location server.For each AP, an AoA heat map is then computed based on the measured AoAphase vectors. Finally, all heat maps of the grouped APs are combined tolocate the client.

Hyperlocation does not scale well because the above correlationcomputation needs to be conducted for each AP and each client, and foreach grid point on a map (or within certain smaller areas). Thus, thelocation server is attempting to make repeatedly all these computationsfor numerous APs, devices, networks, grids, which becomes burdensome ortoo intensive for the processor of the location server.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated in and constitute apart of this disclosure, illustrate various embodiments of the presentdisclosure. In the drawings:

FIG. 1 shows an operating environment for determining a location of adevice in a location where at least part of the determination is made atan AP in accordance with aspects of the present disclosure;

FIG. 2A shows a location, with more than one floor, where a device islocated and where the device's location may be determined frominformation from APs at the location in accordance with aspects of thepresent disclosure;

FIG. 2B is an example of an AP in accordance with aspects of the presentdisclosure;

FIG. 2C is an example of a location server in accordance with aspects ofthe present disclosure;

FIG. 3A shows an example set of Received Signal Strength Indicator(RSSI) measurements from devices on more than one floor of a locationand a corresponding RSSI threshold in accordance with aspects of thepresent disclosure;

FIG. 3B shows another example set of RSSI measurements from devices onmore than one floor of a location and a corresponding RSSI threshold inaccordance with aspects of the present disclosure;

FIG. 4A shows a set of base phase vectors in accordance with aspects ofthe present disclosure;

FIG. 4B shows a result of measured energy values as applied to a set ofbase phase vectors in accordance with aspects of the present disclosure;

FIG. 5 shows visual representations of the base phase vector heat mapsgenerated from projection values received from AP(s) and provided to thelocation server and a heat map generated from that information inaccordance with aspects of the present disclosure;

FIG. 6 shows a signaling diagram in accordance with aspects of thepresent disclosure;

FIG. 7 shows another signaling diagram in accordance with aspects of thepresent disclosure;

FIG. 8A shows a data structure stored, sent, received, or retrieved todetermine a location of a user device in accordance with aspects of thepresent disclosure;

FIG. 8B shows another data structure stored, sent, received, orretrieved to determine a location of a user device in accordance withaspects of the present disclosure;

FIG. 8C shows another data structure stored, sent, received, orretrieved to determine a location of a user device in accordance withaspects of the present disclosure;

FIG. 8D shows another data structure stored, sent, received, orretrieved to determine a location of a user device in accordance withaspects of the present disclosure;

FIG. 9A is a method, conducted by the location server, for determining alocation of a user device in accordance with aspects of the presentdisclosure;

FIG. 9B is another method, conducted by the location server, fordetermining a location of a user device in accordance with aspects ofthe present disclosure;

FIG. 10A is a method, conducted by an AP, for determining a location ofa user device in accordance with aspects of the present disclosure;

FIG. 10B is a method, conducted by an AP, for determining a location ofa user device in accordance with aspects of the present disclosure;

FIG. 11 shows a block diagram of a computer or computing device forconducting or executing the methods and processes for determining alocation of a user device in accordance with aspects of the presentdisclosure.

DETAILED DESCRIPTION

Overview

Offloading of location computation from a location server to an accesspoint through the use of projections on base phase vectors may beprovided. First, an Access Point (AP) may receive a set of two or morebase phase vectors from a location server. Next, the AP may measure ameasured phase vector for a first signal from a user device. Then, theAP can determine projection values based on a comparison of the measuredphase vector to each base phase vector. From these comparisons, the APcan determine a subset of base phase vectors with the highest projectionvalues. The AP can then send the projection values and the subset ofbase phase vectors to the location server, wherein the location serverdetermines the device location from these projection values and subsetof base phase vectors.

Both the foregoing overview and the following example embodiments areexamples and explanatory only, and should not be considered to restrictthe disclosure's scope, as described and claimed. Furthermore, featuresand/or variations may be provided in addition to those described. Forexample, embodiments of the disclosure may be directed to variousfeature combinations and sub-combinations described in the exampleembodiments.

Example Embodiments

The following detailed description refers to the accompanying drawings.Wherever possible, the same reference numbers are used in the drawingsand the following description to refer to the same or similar elements.While embodiments of the disclosure may be described, modifications,adaptations, and other implementations are possible. For example,substitutions, additions, or modifications may be made to the elementsillustrated in the drawings, and the methods described herein may bemodified by substituting, reordering, or adding stages to the disclosedmethods. Accordingly, the following detailed description does not limitthe disclosure. Instead, the proper scope of the disclosure is definedby the appended claims.

As a first step in computing a device's location at the edge, an AP candetermine which floor the device belongs to and then can estimate the X,Y position of the device on the floor. In an enterprise occupying amulti floor building, it can be difficult to come up with a stand-alonedistributed algorithm to determine which floor the device belongs to andhence which APs to consider while computing the location at the edge.This problem is particularly hard due to the different deployments,floor heights, density of APs per floor that are observed in practicaldeployments. Assuming the client's floor to be the same floor as the APcan lead to further problems as the assumption may be incorrect.

The proposed solution to this issue is mainly centered arounddynamically determining a RSSI threshold that the associated AP can useto assume that the device is on the same floor as the AP. The thresholdnot only may depend on the type of floor or building and density of APs,as indicated above, but also on the area on the floor that the AP islocated and serving. The 2 APs we would consider are the red and blueAPs on the 2nd floor. As seen from the figure the red AP is close to anatrium (i.e. an opening in the floor to view the floor

An optimal RSSI threshold can minimize incorrect floor determination andcan be obtained by simple classification techniques like logisticregression or just maximum likelihood. The existing floor determinationalgorithm can be run in the cloud. Although the result may be differentthan the actual floor of the device, the determination is relativelyrobust and has high degree of accuracy. Moreover, this determination isthe best feedback other than getting feedback from the users, which ismanual process and hard to obtain.

In general, the solution can learn or determine an RSSI threshold on thecloud during an initial start-up phase and push these predetermined RSSIthresholds back to the edge on each AP. Thus, in the initial start-upstage, all APs can send all RSSIs to the cloud, which computes the X, Ylocation from the raw RSSIs. The cloud can then estimate and push theper-AP RSSI threshold to the APs. In at least some configurations, theoptimization for the RSSI threshold criteria could be to minimize thetype 2 errors or maximize accuracy.

Then, the AP can user the RSSI threshold to determine if the AP candetermine the floor on which the device is located and then compute theX,Y location of the device on the floor. Evaluation of the threshold canbe: if the associated client RSSI is greater than the RSSI threshold,then the AP computes the location and sends the computed X, Y locationto cloud. IN contrast, if the associated client RSSI is less than theRSSI threshold, then the AP can send the raw AP RSSIs and locations tothe cloud for floor determination and an X, Y compute. The APs knowwhich floor they belong to and the other APs on the floor they areassociated therewith because cloud can notify the APs during thestartup. RSSI of clients associated to APs on the other floors are sentdirectly to cloud, while the RSSI of the client associated to APs on itsown floor can be sent to the associated AP.

Then, the cloud can store the computed X, Y and/or the raw RSSI andcomputes the X, Y for the client. The solution may also auto detect anychanges to the threshold that may occur over time. Thus, the cloud canperiodically run the classification algorithm to determine if theoptimal threshold needs to be changed on the AP based on the RSSIsreported directly to cloud. For example if the raw RSSIs reported mostlyresult in the same floor as the associated AP then Cloud couldpotentially decrease the RSSI threshold. Thus, a gradual descent-typesearch for these optimal thresholds could be initiated iteratively.

Only once the device signal RSSI is greater than the RSSI threshold maythe AP determine location information. The AP can perform at least someof the location calculations, which would push the location computationto the edge without compromising the reliability and robustness of theexisting solution. More specifically, using AP4800 as an example, thereare 16 antennas on each AP. So each phase vector for locationdetermination is a 1-by-16 complex vector. Each AoA heat map is computedby correlating the measured phase vector with ideal phase vectors of allgrid points on the map. A higher correlation value indicates that theuser device is more likely to be on the corresponding grid point (or thesignal is received from the corresponding azimuth angle). After addingtogether all the heat maps of all grouped APs, the grid point with thelargest correlation value is chosen as the client location.

A main reason that hyperlocation is computationally intensive is becausethe above correlation computation of phase vectors needs to be conductedfor each AP and each client, and for each grid point on the map (orwithin certain smaller areas). When the AP has n antennas, each phasevector correlation computation takes n complex multiplications and ncomplex additions. In order to improve scalability of hyperlocation incloud, embodiments herein construct a set of orthogonal base phasevectors and pre-compute the base AoA heat map for each of them.

During location, each AP can project the measured phase vector onto theset of base phase vectors and only reports the top m projections to thecloud. Based on the projections, the cloud weighted-sums the precomputedbase AoA heat maps for location computation. This process reduces thecomputational complexity at the cloud to m/n of its current value, withn being the number of antennas at AP.

To improve the scalability of hyperlocation, the embodiments hereinpropose the following method (by using an AP with 16 antennae): becauseeach phase vector is a 1-by-16 complex vector, it is always within a16-dimensional space. Therefore, if the cloud can compute a set of 16bases for this 16-dimensional space, each phase vector can now berepresented as the following:

$\sum\limits_{i = 1}^{16}\;\left( {{Projection\_ i}*{base\_ phase}{\_ vector}{\_ i}} \right)$

Where projection_i is the projection of the measured phase vector ontothe i^(th) base phase vector (base_phase_vector_i), and wherebase_phase_vector_i is orthogonal to base_phase_vector_j if i does notequal j.

By cleverly selecting the set of 16 base vectors, for each measuredphase vector, most of the information associated with the phase vectorof a signal can be retained with only a small subset of the 16 basevectors (for example, m out of 16, with m<16). In other words, for theabove equation, only a few proj_i are large while the rest of theprojections are small.

Each AP can then report only the m largest projections to the cloud,which are later used by the cloud to weighted-sum the corresponding baseAoA heat maps (base AoA heat maps are the precomputed AoA heat maps forthe base phase vectors) and can reconstruct an AoA heat map for each AP.As a result, the total computation number now reduces to m/16 of theoriginal value.

Finally, the embodiments can combine reconstructed heat maps of all APstogether for location computation. Moreover, the embodiments canpre-compute the 16 base phase vectors and corresponding base AoA heatmaps. It should be noted that only one set of base AoA heat maps need tobe stored per frequency band, because by rotating and shifting the basephase vectors, we can create base AoA heat maps for all APs. During thelocation process, the projection computation happens at each AP, whilethe weighted-sum of base AoA heat maps and the device location searchhappen in cloud.

The base phase vectors roughly point to different angles. There are alsoside-lobes with each base phase vector to ensure that these base phasevectors are orthogonal with each other. In the cloud, the embodimentspre-compute the base AoA heat maps for each of the 16 base phasevectors. It should be noted that this pre-computation only needs to bedone and stored for the first AP, because the base AoA heat maps of theother APs can be derived by rotating and shifting the base AoA heat mapsof the first AP.

During location, after each AP sends the top m projection values to thecloud, the cloud can weighed-sum the corresponding base AoA heat maps toreconstruct the AoA heat map of each AP. Because only m base AoA heatmaps are used, the total number of computations reduces to m/n of itsoriginal value, with n being the number of antennas at AP.

FIG. 1 shows an operating environment 100 for determining a physicallocation of a user device 155 that is communicating with APs in thenetwork 110. As shown in FIG. 1, operating environment 100 may comprisea Location server 105 and a network 110. Location server 105 may collectinformation about network 110 and provide that information to provideuser experiences through the Location server processes and applications.The location information can be used to determine a user's locationphysically, which may be used to provide some type of experience to theuser at the determined location. Location server 105 may also providethose user experiences. Location server 105 may be located inside oroutside network 110, for example, in a cloud environment.

Network 110 may comprise, but is not limited to, an enterprise networkthat may comprise an enterprise's communications backbone that mayconnect computers and related devices across departments and workgroupnetworks, facilitating insight and data accessibility. As shown in FIG.1, network 110 may comprise a router 115, a first network device 120A, asecond network device 120B, and a third network device 120C. A pluralityof end use devices 135 may be connected to one or more of the networkdevices 120. The first plurality of end use devices 135 may comprise atleast a first end use device 155. Generally, the network devices 120 areaccess points. An AP 120 can be any hardware device or configured nodeon a local area network (LAN) that allows a wireless capable device 155and wired networks to connect through a wireless standard, includingWi-Fi or the BLUETOOTH wireless technology standard. APs 120 can featurea processor, radio transmitters, and antennae, which facilitateconnectivity between devices 155 and the network 110. APs 120 can be asdescribed in conjunction with FIG. 11.

The router 115 may comprise a Wide Area Network (WAN) router that mayconnect network 110 to an external network, for example, the Internet.When Location server 105 is located outside network 110, router 115 mayconnect Location server 105 with network devices (e.g., AP 120) in thenetwork 110.

Each of user devices 155 may comprise, but is not limited to, a cellularbase station, a tablet device, a mobile device, a smartphone, atelephone, a remote control device, a set-top box, a digital videorecorder, a cable modem, a personal computer, a network computer, amainframe, a router, or other similar microcomputer-based device capableof accessing and using network 110.

The elements described above of operating environment 100 (e.g.,Location server 105, router 115, AP 1 120A, AP 2 120B, AP 3 120C, enduser device 155, etc.) may be practiced in hardware and/or in software(including firmware, resident software, micro-code, etc.) or in anyother circuits or systems. The elements of operating environment 100 maybe practiced in electrical circuits comprising discrete electronicelements, packaged or integrated electronic chips containing logicgates, a circuit utilizing a microprocessor, or on a single chipcontaining electronic elements or microprocessors. Furthermore, theelements of operating environment 100 may also be practiced using othertechnologies capable of performing logical operations such as, forexample, AND, OR, and NOT, including but not limited to, mechanical,optical, fluidic, and quantum technologies. As described in greaterdetail below with respect to FIG. 11, the elements of operatingenvironment 100 may be practiced in a computing device 1100.

Consistent with embodiments of the disclosure, AP 120 may be incommunication with a user device 155 in which the location of the userdevice 155 is desired. The physical location may be determined from aReal Time Location Service (RTLS). The functions of the RTLS may besplit between the APs 120 and the location server 105. Accordingly, asdescribed in greater detail below, embodiments of the disclosure mayprovide a process by which location services for determining a userdevice location may be conducted partly by the APs 120 and partly by thelocation server 105

FIG. 2A shows a location 200 having one or more APs 120A-120E. Each ofthe APs 120 may be located in a predetermined and known position withinlocation 200. The APs 120 can communicate wirelessly with a mobiledevice 155. While the mobile device 155 is exemplary of other devicesthat may be in the location 200, while device 155 is mobile, it may bepossible to communicate with other devices that are stationary todetermine an initial position of such stationary devices. Each of theAPs 120 can conduct at least a portion of the location services asdescribed herein.

The location 200 can also have more than one floor, for example, floor 1201 and floor 2 202. The presence of two or more floors complicates thelocation process. A simple X, Y coordinate may not accurately indicatethe location of the device 155, which is on the second floor 202 oflocation 200. Thus, the APs 120 can also measure the RSSI of the signalreceived from the device 155. If the RSSI is over some predeterminedthreshold, the AP 120 can determine that the device 155 is on a samefloor as the AP 120. In this way, at least a general indication of the“vertical” location (e.g., the floor the device 155 is on) of the device155 is determined.

FIG. 2B shows an example of an AP 120. The AP 120 can include at least aportion of the RTLS 204A. Thus, the RTLS 204A can include at least aportion of the hardware and/or software used to determine the locationof a device 155 within location 200. In at least some configurations,the AP 120 may include a RSSI threshold evaluator 206 and a base phasevector assigner 208. The RSSI threshold evaluator 206 can receive anRSSI threshold from the location server 105. The RSSI is a measure ofsignal strength, which can be measured or determined for incomingsignals from the device 155. The RSSI threshold evaluator 206 cancompare this measured signal to the received threshold. If the measuredsignal is above the threshold, the RSSI threshold evaluator 206 candetermine that the device 155 is on a same floor 202 as the AP 120 andallow the location process to determine an X, Y location for the device155 on the floor 202.

The base phase vector assigner 208 can receive a set of base phasevectors from the location server 105. The base phase vectors may be asdescribed in conjunction with FIG. 4A. When receiving a signal from thedevice 155 and determining the device's location, the base phase vectorassigner 208 can conduct searches or determine the best base phasevectors that correlate to the AoA of a signal from the mobile device155. The AoA of the signal from the mobile device 155 may be determinedby the Time Of Arrival (TOA) and/or the RSSI of the signal from themobile device 155 as the signal reaches the one or more antennasassociated with the AP 120.

The base phase vector assigner 208 can then determine at least one basephase vector that correlates with the AoA of the signal from the mobiledevice 155 to be forwarded to the location server 105. The base phasevector assigner 208 can assign a projection value to the base phasevector(s) and provide the projection value to the location server 105 torecompose a heat map associated with the device's signal. In this way, areduced amount of processing is done on the AP 120 and lesscommunication traffic is needed between the AP 120 and the locationserver 105.

An exemplary embodiment of the location server 105 may be a shown inFIG. 2C. The location server 105 can include at least a second portionor the remainder of the RTLS 204B. The RTLS 204B can be, within thelocation server 105, any software and/or hardware. Generally, the RTLS204B can include one or more of, but is not limited to, a RSSI thresholddeterminer 212 (which can be a part of a Cloud Location System Manager),a base phase vector assessor 214 (which can also be a part of a CloudLocation System Manager), and/or a heat map generator 216 (which can bea part of a Cloud Location Computation Engine). The RSSI thresholddeterminer 212 can determine, from past RSSI measurements and locationdeterminations of devices within location 200, the RSSI threshold to beused by one or more APs 120 on each floor of the location 200 todetermine that a device 155 is on the same floor as the APs 120. Assuch, the location server 105 can send an AP-specific RSSI threshold foreach AP 122 to compare to a measure or received RSSI of the signal froma mobile device 155. The function of the RSSI threshold may be asdescribed hereinafter.

The base phase vector assessor 214 can determine a set of base phasevectors for an AP 120. An exemplary set of base phase vectors may be asshown in FIG. 4A. The first set of base phase vectors may then bemodified by the base phase vector assessor 214, by rotating and aligningthe base phase vectors, to apply to the other APs 120. As such, acustomized set of base phase vectors for each AP 120 can be generated bythe base phase vector assessor 214 and sent to the applicable AP 120.

The heat map generator 216 can receive the location information from twoor more of the APs 120. From the AOA information, the heat map generator216 may be capable of determining a likely position of the device 155within the location 200. Thus, the heat map generator 216 is operable todetermine a coordinate position based on the projection of the measuredphase vectors on the base vectors, as described hereinafter. This datahelps determine the likely location of the mobile device 155 based onthe known locations of the different APs 120.

An example of the RSSI results 300 and an exemplary RSSI threshold 304for a first AP 120 may be a shown in FIG. 3A. The AP 120, for example AP120D, may be on a second floor 202 and isolated from any large openingto the floor below 201. Thus, it may not be possible for AP 120D toreceive signals, with high RSSI values, from devices on a first floor201. Thus, signals from devices on a first floor 201 may be included ingroup 312, where these signals have a lower RSSI as placed on thehorizontal axis 308 measured in decibels (dBs). In contrast, the signalsfrom devices on the second floor 202 with the AP 120D may be in group316 with higher dB values.

Based on these measurements, the location server 105 can establish aRSSI threshold 304. The RSSI threshold 304 can be compared to receivedsignals from devices. If the RSSI of the signal is above the threshold,the AP 120D can determine that the devices is on the same floor, e.g.,the second floor 202, with the AP 120D. Likewise, if the RSSI of thesignal is below the RSSI threshold 304, the AP 120D can determine thatthe device is on a different floor, e.g., floor 1 201, and foregoproviding a location for this device. Using the RSSI threshold 304, eachAP 120 can make a determination of the vertical position of the deviceand provide a location only when the device is on the same floor, whichmake the location determinations more accurate.

Another example of the RSSI results 316 and another exemplary RSSIthreshold 320 for a second AP 120 may be a shown in FIG. 3A. The AP 120,for example AP 120A, may be on a second floor 202 but nearer a largeopening to the floor below 201. Thus, AP 120A can receive signals, withhigher RSSI values, from devices on a first floor 201. Signals fromdevices on a first floor 201 may be included in group 324, where atleast some of these signals have a lower RSSI as placed on thehorizontal axis 308. However, some of the signals in group 324 havehigher RSSI values although the devices are on the first floor 201. Incontrast, the signals from devices on the second floor 202 with the AP120A may be in group 316 with higher dB values. As can be seen in FIG.3B, the RSSI values for signals received from devices on the first floor201 and the second floor 202 are intermixed, which makes setting theRSSI threshold 320 more difficult.

Based on the measurements 316, the location server 105 can establish aRSSI threshold 320 that is above the highest RSSI value 332 of a signalreceived from a device on a first floor 201. The placement of this RSSIthreshold 320 ensures that no device on a first floor 201 will bedetermined to be on the second floor 202. However, some devices on thesecond floor 202 may be determined not to be on the second floor 202. Assuch, false positives are eliminated but false negatives occur. Tocompensate for this situation, the RSSI threshold determiner 212 cancompare the results from AP 120A with results from other APs on the samefloor 202, e.g., AP 120D. If the other AP believes the device to be onthe second floor 202, location information from the AP 120A can beaccepted.

As explained above, the RSSI threshold 320 can be compared to receivedsignals from devices. If the RSSI of the signal is above the threshold,the AP 120A can determine that the devices is on the same floor, e.g.,the second floor 202, with the AP 120A. Likewise, if the RSSI of thesignal is below the RSSI threshold 320, the AP 120A can determine thatthe device may be on a different floor, e.g., floor 1 201. However,unlike the description above, AP 102A would send the received RSSIinformation and the location information to the location server 105 incase the determination was a false negative. The RSSI and locationinformation can be sent from any AP 120 periodically or based on otherdetermination to better improve the accuracy of the RSSI thresholds 304,320. The updating of the RSSI threshold 320 is especially useful insituations as shown in FIG. 3B when the RSSI threshold is harder todetermine.

An embodiment of a set 400 of example base phase vectors 402 a-402 p maybe a shown in FIG. 4. Each base phase vector 402 a-402 p roughly pointsto a different azimuth angle. Side lobes may be included in the basephase vectors 402 to ensure that the bases are generally orthogonal toeach other. The base phase vectors 402 can be rotated and aligned foreach AP 120. Further, the base phase vectors 402 are associated with acorresponding heat map stored at the location server 105. Providing anindication of what base phase vector is most closely related to ameasured phase vector allows the location server 105 to determine thebest heat map to use for the location determination, as explainedhereinafter.

The received phase vector of the signal from the device 155 can beevaluated against the base phase vectors to determine the closestmatch(es), as shown in chart 404 in FIG. 4B. Thus, the highestcorrelation, for example, base vector 9 402 i indicates the AoA for thesignal is most closely related to that base phase vector. The AP 120 canreport one or more of the base phase vectors to the location server 105to use one or more corresponding heat maps for the locationdetermination.

Examples of the heat maps that may be generated based on the base phasevector output from various APs 120 may be as shown in FIG. 5. Forexample, each AP 120 may provide a set of the top base phase vectors.These base phase vectors are each associated with a heat map. The one ormore heat maps from each AP may be combined and weighted based on thecorrelation to the base phase vector. The combined heat maps andweightings are represented by the bands shown in FIGS. 504A-504D. Thebrightness of the band, for example, light grey, represents a higherprobability that the signal from the device 155 arrived at an AoAassociated with that base phase vector 402. Thus, each AP 120 mayprovide a limited set of AOA information for that AP 120 and restrictedto a number of top base phase vectors.

The location server 105 may then combine this heat map information fromthe APs 120 to form a combined heat map, for example, heat map 508.Thus, the combination of the various AOA information can be quicklyassimilated into a heat map 508 that indicates, with relative accuracy,the location of the device 155 within location 200. This heat map 508provides the most probable location of the device 155, and the locationserver 105 may send this physical position to other services or devicesfor use in other applications.

FIG. 6 is a signalling diagram 600 that shows a least some of thecommunications between the AP 120 and the location server 105. Thesignals may be sent in various stages to determine the location of adevice 155 within area 200. An AP 120 can send location information insignal 604. This initial signal(s) 604 can provide initial locationinformation from other devices to allow the location server 105 todetermine the RSSI threshold 304/320, in process 608. This previouslocation information, used to determine the RSSI threshold 304/320, isthen composed into a directive to the AP 120 in signal 612 and sent tothe AP 120.

From the information in signal 612, the AP 120 can filter out signalsfrom devices with an RSSI below the RSSI threshold 304/320. The locationdetermination for a new device 155 can occur in stage 616. The locationinformation, from devices that have an RSSI above the threshold, may besent from the AP 120 to the location server 105 in signal 624. However,location information, from devices that have an RSSI below thethreshold, may either not be sent or may be sent from the AP 120 to thelocation server 105 in signal 620. Signal 620 may include RSSIinformation and location information. From the new RSSI information insignal 620, the location server 105 may refine the RSSI threshold304/320. The refined or adjusted RSSI threshold 304/320 can then be sentback to the AP 120 in signal 632 for user in future comparisons to theRSSI threshold 304/320.

FIG. 7 is another signalling diagram 700 that shows a least some of theother communications between the AP 120 and the location server 105. Thesignals may be sent in various stages to determine the location of adevice 155 within area 200. An AP 120 can send location information insignal 704. This initial signal(s) 704 can provide initial locationinformation from other devices to allow the location server 105 todetermine a set 400 of base phase vectors 402 for the AP 120 in process708. This previous location information, used to determine the set 400of base phase vectors 402. The set 400 of base phase vectors 402 is thencomposed into a directive to the AP 120 in signal 712 and sent to the AP120.

From the set 400 of base phase vectors 402 in signal 712, the AP 120 cancompare the received signals phase vector to the set 400 of base phasevectors 402 to locate device 155. The similar base phase vectors 402determination for a new device 155 can occur in stage 716. The basephase vectors 402 information from this determination may be sent insignal 720 back to the location server 105. The base phase vectors 402information in signal 720, from the various APs 120, can be used tocompose the heat map 508 in process 724. This heat map can indicated aphysical location for the device 155, which location can be provided toother processes or devices.

FIG. 8A is a data structure 800 that may be an example of the dataincluded in signal 604 or signal 620. The data structure 800 can includeone or more of, but is not limited to an AP Identifier (ID) 802, deviceID 803, an RSSI measurement 804, and/or azimuth coordinates 806. Thedata structure 800 can include more or fewer fields than those shown inFIG. 8A, as represented by ellipses 808. Further, each AP 120, in thelocation 200, can send a data structure 800, and thus, there may be moredata structures provided than that shown in FIG. 8A, as represented byellipses 810, based on the number of APs 120 in the location 200.

The AP ID 802 can represent any type of identifier that uniquelyidentifies the AP 120 from other APs 120 in the network 110. Thus, theAP ID 802 can be a numeric ID, and alphanumeric ID, an Internet Protocol(IP) address, a MAC address, or some other address or ID used by thelocation server 105 to send the signal 712 to the AP 120 and recognizewhich AP 120 is sending the AoA information in signal 720.

The device ID 803 can represent any type of identifier that uniquelyidentifies the device 155 from other devices in the network 110. Thus,the device ID 803 can be a numeric ID, and alphanumeric ID, an InternetProtocol (IP) address, a MAC address, a phone number, or some otheraddress or ID used by the AP 120 and location server 105 to identify thedevice 155 for location services with the AP 120 and the location server105.

The RSSI measurement(s) 803 can be a measurement of the RSSI for asignal associated with a signal from the device 155. As explainedpreviously, past location and RSSI determinations or measurements 804from the APs 120 may be provided to the location server 105. With thedevice ID 803, the location server 105 can review the RSSI measurements804 and location determinations from APs 120 on the same floor. Fromthis information, the location server 105 can determine whether thedevice is on the same floor as the AP 120 sending the information. Aftersome number of RSSI measurements 804 are received, the location server105 can establish the RSSI thresholds 810 for the AP 120 based onfiltering out signals likely sent from a device on another floor.

The azimuth coordinates 806 can be an identification or designation ofthe location of a device for which the AP 120 has monitored. Asexplained previously, past AoA determinations 806, from the APs 120, maybe used to determine a location of a device previously. These pastmeasurements 806 may help in determining the best base phase vectors822. An AP 120 may receive signals more often from a device 155 in someportion of the AP's area of coverage because of the physical environmentin which the AP 120 operates. This information may be evidenced from thepast azimuth measurements 806 and can help inform the selection of abase set of phase vectors.

FIG. 8B is another data structure 812 that may be an example of the dataincluded in signal 612 or signal 632. The data structure 812 can includeone or more of, but is not limited to the AP ID 802 and/or a RSSIthreshold 810. The data structure 812 can include more or fewer fieldsthan those shown in FIG. 8B, as represented by ellipses 814. Further,each AP 120 in the location 200 can send a data structure 812, and thus,there may be more data structures provided than that shown in FIG. 8A,as represented by ellipses 816. The AP ID 802 may be as previouslydescribed with data structure 800, and thus, will not be explainedfurther.

The RSSI threshold 810 can be an RSSI value, likely in dBs, to which theAP 120 is to compare the RSSI measured from incoming signals. The RSSIthreshold 810 is set by the location server 105, as explainedpreviously, so that the AP 120 can filter out signals from devices noton the same floor as the AP 120. Thus, the AP 120 need not determine thelocation of a device with a signal below the RSSI threshold 810.However, in some circumstances, the AP 120 may still determine thelocation of devices with a signal below the RSSI threshold 810. In thesesituations, the AP 120 may send the location information with the RSSImeasurement 804 back to the location server 195.

FIG. 8C is another data structure 818 that may be an example of the datain signal 712 as provided from the location server 105 to the AP 120.The data structure 818 can include one or more of, but is not limitedto, the AP ID 802, the device ID 814, and/or a set of base phasevectors. The data structure 818 can include more or fewer fields thanthose shown in FIG. 8C, as represented by ellipses 828. Further, eachdevice 155 in the location 200 can have a different location, and thus,there may be more data structures 818 provided than that shown in FIG.8C, as represented by ellipses 826. The AP ID 802 and device ID 814 maybe as previously described with data structure 800, and thus, will notbe explained further.

The set of base phase vectors 820 can include any of the informationrequired by the AP 120 to describe the base phase vectors 402. Thisinformation can include an identifier for the base phase vector 402 andother associated information. For example, the base phase vectorinformation can include one or more of a complex number, datarepresenting a sinusoidal function whose Amplitude (A), angularfrequency (ω), and initial phase (θ) are time-invariant. Regardless ofthe information that could be provided, the information in the set ofbase phase vectors 820 allows the AP to compare a measured phase vectorto each of the base phase vectors in the set of base phase vectors 820.

FIG. 8D is another data structure 818 that may be an example of the datadetermined by and provided from AP 120 in signal 720. The data structure830 can include one or more of, but is not limited to, the AP ID 802,the device ID 814, a phase vector measurement 822, one or more basephase vectors 824, and/or weights 826. The data structure 830 caninclude more or fewer fields than those shown in FIG. 8D, as representedby ellipses 832. Further, each device 155 in the location 200 can have adifferent location, and thus, there may be more data structures 830provided than that shown in FIG. 8C, as represented by ellipses 836. TheAP ID 802 and device ID 814 may be as previously described with datastructures 800 and/or 812, and thus, will not be explained further.

The phase vector measurement 820 can be a measurement of the phasevector for a signal received from a device 155 as calculated by the AP120. The phase vector measurement 820 may be stored by the AP 120 forcomparison to the set of base phase vectors 820. As such, the phasevector measurement 820 is at least somewhat similar to one or more basephase vectors 402, as shown in FIG. 4.

The base phase vector(s) 822 are a subset of one or more of the basephase vector(s) 820. The base phase vector(s) 822 include the base phasevectors 402 that are most similar to the phase vector measurement 820.The number of base phase vector(s) 822 to include in the subset may bebased on a setting provided from the location server 105, from userinput, as set by a factory, or based on other input. Each of these basephase vector(s) 822 also relates or is associated with a heat map forthat base phase vector(s) 402. The various heat maps associated with thebase phase vector(s) 822 can be combined into a combined heat map, e.g.,heat map 504, as shown in FIG. 5. These combined heat maps can then befurther combined for all APs to obtain the heat map 508 which indicatesa location of the user device 155.

The weight 826 can be a value for the projection of the phase vectormeasurement 820 onto the base phase vector(s) 822. The more closelyrelated, the higher the projection value. Thus, the location server 105can use this projection value to weight or consider more the heat mapassociated with the base phase vector(s) 822 with higher projectionvalues. The weight 826 or projection value can have any type of value,for example, a decimal number between 0 to 1, 1 being the highest.

An embodiment of a method 900, as conducted by the location server 105,for determining a location of a user device 155 may be as shown in FIG.9A. A general order for the stages of the method 900 is shown in FIG.9A. Generally, the method 900 starts with a start operation 904 and endswith an end operation 932. The method 900 can include more or fewerstages or can arrange the order of the stages differently than thoseshown in FIG. 9A. The method 900 can be executed as a set ofcomputer-executable instructions executed by a computer system andencoded or stored on a computer readable medium. Further, the method 900can be performed by gates or circuits associated with a processor, anApplication Specific Integrated Circuit (ASIC), a Field ProgrammableGate Array (FPGA), a System-On-Chip (SOC), or other hardware device.Hereinafter, the method 900 shall be explained with reference to thesystems, components, devices, modules, software, data structures, heatmaps, methods, etc. described in conjunction with FIGS. 1-8 and 9B-11.

The location server 105 can receive, from at least one of the APs 120connected to the network 110, a location determination (coordinates) anda RSSI measurement, as signal 604, in stage 908. This result may beassociated with a past search. These past search results or pastlocation determinations may be saved by the location server 105 andassociated with the AP 120 that provided the information. For eachdevice 155, the location server 105 can determine the location of thedevice 155, in particular, the floor on which the device 155 is located,in stage 912.

After some number of locations and RSSI measurements are received, thelocation server can determine the RSSI threshold 810 to which an AP 120can determine if a device 155 is no a same floor 202, in stage 916. Thedetermination in stage 916 may be made through various processes oralgorithms, including, but not limited to, logistic regression or justmaximum likelihood. This determined RSSI threshold may then be sent, instage 928, as signal 612.

Further, in some configurations, the AP 120 may use the RSSI thresholdto determine if a device is on the same floor with the AP 120. However,when the RSSI of the signal is below the RSSI threshold, the AP 120 cansend new location information and RSSI information. Thus, the locationserver 105 may receive a new location determination, in step 920. Thelocation determination may be as described below. However, the locationserver 105 may also receive a new RSSI measurement, in optional stage924. If new RSSI information is received, the process 900 may repeat thedetermination of the RSSI threshold, in stage 916.

An embodiment of a method 936, as conducted by the location server 105,for determining a location of a user device 155 may be as shown in FIG.9B. A general order for the stages of the method 936 is shown in FIG.9B. Generally, the method 936 starts with a start operation 940 and endswith an end operation 976. The method 936 can include more or fewerstages or can arrange the order of the stages differently than thoseshown in FIG. 9B. The method 936 can be executed as a set ofcomputer-executable instructions executed by a computer system andencoded or stored on a computer readable medium. Further, the method 936can be performed by gates or circuits associated with a processor, anASIC, a FPGA, a SOC, or other hardware device. Hereinafter, the method936 shall be explained with reference to the systems, components,devices, modules, software, data structures, heat maps, methods, etc.described in conjunction with FIGS. 1-9A and 10A-11.

The location server 105 can receive, from at least one of the APs 120connected to the network 110, a location determination result as signal704. This result may be associated with a past search. These past searchresults or past location determinations may be saved by the locationserver 105 and associated with the AP 120 that provided the information.In at least some configurations, after some number of results arereceived, the location server 105 can determine a set of base phasevectors 400 for the AP 120, in stage 944.

For each subsequent AP 120 after the first AP 120, the location server105 can align the base phase vectors for that AP, in stage 948, androtate the base phase vectors for that AP 120, in stage 952. Likewise,the heat maps associated with the base phase vectors can also be alignedand rotated as necessary. These aligned and rotated base phase vectors400 may then be sent to the AP 120, in stage 960, as signal 712. Thelocation server 105 may then determine if there is another AP 120 thatrequires a set of base phase vectors 400, in stage 960. If another AP120 needs the base phase vectors 400, the process may return “Yes” tostage 948. If no other AP 120 needs the base phase vectors 400, theprocess may proceed “No” to stage 964.

Then, the location server 105 can receive a signal 720 from an AP 120,in stage 964. The signal 720 can include a subset of the base phasevectors 824 and weights 826 associated with the base phase vectors 402associated with AoA for a received signal at the AP 120. In at leastsome configurations, the location server 105 receives the subset of thebase phase vectors 824 and weight 818 based on a predetermined number ofbase phase vectors 824 that are to be sent to the location server 105from the AP 120.

From the base phase vectors 824, the location server 105 can retrievethe heat maps associated with the base phase vectors 824. These heatmaps 504 can be combined into a combined heat map 508 to determine thedevice location, in stage 968. The retrieved heat maps may also beweight some of the base phase vectors 824 based on the weights 826, suchthat the more significant base phase vectors are more prominently shown.From the combined heat map 508, the location server can identify thedevice location in the location 200. This coordinate location may beprovided to other services or devices that require the location toprovide functionality to the user or others, in stage 972.

An embodiment of a method 1000, as conducted by an AP 120, fordetermining a location of a user device 155 may be as shown in FIG. 10A.A general order for the stages of the method 1000 is shown in FIG. 10A.Generally, the method 1000 starts with a start operation 1004 and endswith an end operation 1036. The method 1000 can include more or fewerstages or can arrange the order of the stages differently than thoseshown in FIG. 10A. The method 1000 can be executed as a set ofcomputer-executable instructions executed by a computer system andencoded or stored on a computer readable medium. Further, the method1000 can be performed by gates or circuits associated with a processor,an ASIC, a FPGA, a SOC, or other hardware device. Hereinafter, themethod 1000 shall be explained with reference to the systems,components, devices, modules, software, data structures, heat maps,

The AP 120 can send to the location server 105 connected to the network110, a location determination (coordinates) and a RSSI measurement, assignal 604, in stage 1008. This result may be associated with a pastsearch. These past search results or past location determinations may besaved by the AP 120 and associated with the AP 120 that provided theinformation.

A determined RSSI threshold 810 may then be received, in stage 1012, assignal 612. The AP 120 may then receive a new signal from a user device155, in stage 1016. In some configurations, the AP 120 may use the RSSIthreshold 810 to determine if the device 155 is on the same floor withthe AP 120. Thus, the AP 120 compares the RSSI of the new signal,received in stage 1016, with the RSSI threshold received in stage 1016.The AP 120 determines if the RSSI of the new signal is above the RSSIthreshold 810, in stage 1020.

When the RSSI of the new signal is below the RSSI threshold, the processproceeds “NO” to stage 1028. In stage 1028, the AP 120 can send newlocation information and, in stage 1032, can send new raw RSSImeasurement information to the location server 105. Thus, the locationserver 105 may receive a new location determination and may also receivea new RSSI measurement to adjust the RSSI threshold 810, if necessary.If the RSSI of the new signal is above the RSSI threshold, the processproceeds “YES” to stage 1024, where the AP 120 send location informationto the location server 105, as described hereinafter.

An embodiment of a method 1040, as conducted by an AP 120, fordetermining a location of a user device 155 may be as shown in FIG. 10B.A general order for the stages of the method 1040 is shown in FIG. 10B.Generally, the method 1040 starts with a start operation 1044 and endswith an end operation 1072. The method 1040 can include more or fewerstages or can arrange the order of the stages differently than thoseshown in FIG. 10B. The method 1040 can be executed as a set ofcomputer-executable instructions executed by a computer system andencoded or stored on a computer readable medium. Further, the method1040 can be performed by gates or circuits associated with a processor,an ASIC, a FPGA, a SOC, or other hardware device. Hereinafter, themethod 1040 shall be explained with reference to the systems,components, devices, modules, software, data structures, heat maps,methods, etc. described in conjunction with FIGS. 1-10A and 11.

The AP 120 can send to the location server 105, a location determinationresult as signal 704. This result may be associated with a past search.These past search results or past location determinations may be savedby the location server 105 and associated with the AP 120 that providedthe information. In at least some configurations, after some number ofresults are received, the location server 105 can determine a set ofbase phase vectors 400 for the AP 120. This set 400 of M number of basephase vectors 402 may be received by the AP 120, in stage 1048. The basephase vectors 402 may be rotated and aligned for the AP 120 and theposition of the AP.

Thereinafter, the AP 120 can receive a new signal from a device 155 inlocation 200, in stage 1052. The AP 120 can then measure the phasevector for the new signal, in stage 1056. This measured phase vector maythen be projected onto each of the base phase vectors as a comparisonbetween the measured phase vector and each of the base phase vectors.From this comparison, the AP 120 can derive a projection for each basephase vector 402, in step 1064. Higher the projection values indicatemore correlation between the measured phase vector and the base phasevector. These projection values can become weights for the clouds serverlater.

Based on the projection values, the AP 120 can extract a subset of thebase phase vectors 824. The subset of base phase vectors 824 can befewer base phase vectors 420 than are in the original set 820. Thelocation server 105 can indicate to the AP 120 through a setting howmany base phase vectors are to be in the subset 824. This subset of basephase vectors 824 and the associated projection values (or weights) isthen composed into data structure 830 for signal 720, which is sent tothe location server 105, in stage 1068.

FIG. 11 shows computing device 1100. As shown in FIG. 11, computingdevice 1100 may include a processing unit 1110 and a memory unit 1115.Memory unit 1115 may include a software module 1120 and a database 1125.While executing on processing unit 1110, software module 1120 mayperform, for example, processes for determining a RSSI or base phasevector of a device signal, sending that location information to alocation server, or determining a coordinate location of that devicebased on at least the received location information, including forexample, any one or more of the stages from method 800 or method 900described above with respect to FIG. 8 and FIG. 9. Computing device1100, for example, may provide an operating environment for elements ofoperating environment 100 including, but not limited to, Location server105, router 115, AP 120, and user device 155. Elements of operatingenvironment 100 (e.g., Location server 105, router 115, AP 120, and userdevice 155) may operate in other environments and are not limited tocomputing device 1100.

Computing device 1100 may be implemented using a Wireless Fidelity(Wi-Fi) access point, a cellular base station, a tablet device, a mobiledevice, a smart phone, a telephone, a remote control device, a set-topbox, a digital video recorder, a cable modem, a personal computer, anetwork computer, a mainframe, a router, a switch, a server cluster, asmart TV-like device, a network storage device, a network relay device,or other similar microcomputer-based device. Computing device 1100 maycomprise any computer operating environment, such as hand-held devices,multiprocessor systems, microprocessor-based or programmable senderelectronic devices, minicomputers, mainframe computers, and the like.Computing device 1100 may also be practiced in distributed computingenvironments where tasks are performed by remote processing devices. Theaforementioned systems and devices are examples and computing device1100 may comprise other systems or devices.

Accordingly, aspects of the present disclosure comprise a methodcomprising: receiving a set of two or more base phase vectors;measuring, by an Access Point (AP) in a network, a measured phase vectorfor a first signal from a user device; determining projection valuesbased on a comparison of the measured phase vector to each base phasevector; determining subset of base phase vectors with the highestprojection values; and sending the projection values and the subset ofbase phase vectors to the location server, wherein the location serverdetermines the device location from the projection values and the subsetof base phase vectors.

Any of the one or more above aspects, wherein the subset of base phasevectors is one base phase vector.

Any of the one or more above aspects, wherein each base phase vector isassociated with a heat map.

Any of the one or more above aspects, wherein, if there are more thanone base phase vector in the subset, combining the heat maps associatedwith each base phase vector.

Any of the one or more above aspects, wherein the projection values forthe subset of base phase vectors determine a weight of the heat map.

Any of the one or more above aspects, wherein the two or more base phasevectors are each at a different angle.

Any of the one or more above aspects, wherein the two or more base phasevectors are orthogonal to each other.

Any of the one or more above aspects, further comprising: receiving anRSSI threshold from the location server; determining a RSSI value forthe first signal from the user device; comparing the determined RSSIvalue to the RSSI threshold; and if the determined RSSI value is abovethe RSSI threshold, providing location information about the user deviceto the location server.

Any of the one or more above aspects, wherein if the determined RSSIvalue is not above the RSSI threshold, the AP: providing the locationinformation and the determined RSSI value about the signal from the userdevice to the location server; or not providing location information tothe location server.

Any of the one or more above aspects, wherein if the determined RSSIvalue is above the RSSI threshold, the user device is on a same floor asthe AP.

Aspects of the present disclosure further comprise a method comprising:receiving, by a location server, two or more signals, having locationinformation and RSSI information from two or more Access Points (APs)associated with a location of a user device, based on the RSSIinformation, generating an RSSI threshold for each AP; sending the RSSIthreshold to each AP; receiving a projection value and a base phasevector from each AP; based on the projection values and the base phasevectors, generating a combined heat map that indicates the location ofthe user device.

Any of the one or more above aspects, wherein each base phase vector hasan associated heat map.

Any of the one or more above aspects, wherein generating a combined heatmap comprises combining the associated heat maps from each base phasevector from each AP into the combined heat map.

Any of the one or more above aspects, further comprising receiving theprojection value and the base phase vector with new RSSI information.

Any of the one or more above aspects, wherein the new RSSI informationindicates that the user device is not on the same floor as the AP, themethod further comprising: adjusting the RSSI threshold based on the newRSSI information

Aspects of the present disclosure further comprise a system comprising:a network; a first Access Point (AP) in communication over the network,the first AP comprising: a memory storage; a processing unit coupled tothe memory storage, wherein the processing unit is operative to: receivean RSSI threshold from a location server; receive a set of two or morebase phase vectors; receive a first signal from a user device; based onreceiving the first signal, determine an RSSI value for the first signalfrom the user device; compare the determined RSSI value to the RSSIthreshold; if the determined RSSI value is above the RSSI threshold:measure a measured phase vector for the first signal; determineprojection values based on a comparison of the measured phase vector toeach base phase vector; determine subset of base phase vectors with thehighest projection values; and send the projection values and the subsetof base phase vectors to the location server in a second signal; thelocation server in communication with the AP over the network, thelocation server comprising: a second memory storage; and a secondprocessing unit coupled to the second memory storage, wherein the secondprocessing unit is operative to: receive location information and RSSIinformation from the first AP associated with a location of the userdevice, based on the RSSI information, generate the RSSI threshold; sendthe RSSI threshold to the first AP; receive a set of projection valuesand base phase vectors from the first AP; and based on the projectionvalues and the base phase vectors, generate a combined heat map thatindicates the location of the user device.

Any of the one or more above aspects, wherein each base phase vector hasan associated heat map, and wherein generating a combined heat mapcomprises combining the associated heat maps from each base phase vectorinto the combined heat map.

Any of the one or more above aspects, wherein the second processing unitis further operative to receive the projection value and the base phasevector with new RSSI information, wherein the new RSSI informationindicates that the user device is not on the same floor as the first AP;and adjust the RSSI threshold based on the new RSSI information.

Any of the one or more above aspects, wherein the two or more base phasevectors are each at a different angle, and wherein the two or more basephase vectors are orthogonal to each other.

Any of the one or more above aspects, wherein the projection values forthe subset of base phase vectors determines a weight of the combinedheat map.

Embodiments of the disclosure, for example, may be implemented as acomputer process (method), a computing system, or as an article ofmanufacture, such as a computer program product or computer readablemedia. The computer program product may be a computer storage mediareadable by a computer system and encoding a computer program ofinstructions for executing a computer process. The computer programproduct may also be a propagated signal on a carrier readable by acomputing system and encoding a computer program of instructions forexecuting a computer process. Accordingly, the present disclosure may beembodied in hardware and/or in software (including firmware, residentsoftware, micro-code, etc.). In other words, embodiments of the presentdisclosure may take the form of a computer program product on acomputer-usable or computer-readable storage medium havingcomputer-usable or computer-readable program code embodied in the mediumfor use by or in connection with an instruction execution system. Acomputer-usable or computer-readable medium may be any medium that cancontain, store, communicate, propagate, or transport the program for useby or in connection with the instruction execution system, apparatus, ordevice.

The computer-usable or computer-readable medium may be, for example butnot limited to, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, apparatus, device, or propagationmedium. More specific computer-readable medium examples (anon-exhaustive list), the computer-readable medium may include thefollowing: an electrical connection having one or more wires, a portablecomputer diskette, a Random Access Memory (RAM), a read-only memory(ROM), an Erasable Programmable Read-Only Memory (EPROM or Flashmemory), an optical fiber, and a portable Compact Disc Read-Only Memory(CD-ROM). Note that the computer-usable or computer-readable mediumcould even be paper or another suitable medium upon which the program isprinted, as the program can be electronically captured, via, forinstance, optical scanning of the paper or other medium, then compiled,interpreted, or otherwise processed in a suitable manner, if necessary,and then stored in a computer memory.

While certain embodiments of the disclosure have been described, otherembodiments may exist. Furthermore, although embodiments of the presentdisclosure have been described as being associated with data stored inmemory and other storage mediums, data can also be stored on or readfrom other types of computer-readable media, such as secondary storagedevices, like hard disks, floppy disks, or a CD-ROM, a carrier wave fromthe Internet, or other forms of RAM or ROM. Further, the disclosedmethods' steps or stages may be modified in any manner, including byreordering steps or stages and/or inserting or deleting steps or stages,without departing from the disclosure.

Furthermore, embodiments of the disclosure may be practiced in anelectrical circuit comprising discrete electronic elements, packaged orintegrated electronic chips containing logic gates, a circuit utilizinga microprocessor, or on a single chip containing electronic elements ormicroprocessors. Embodiments of the disclosure may also be practicedusing other technologies capable of performing logical operations suchas, for example, AND, OR, and NOT, including but not limited to,mechanical, optical, fluidic, and quantum technologies. In addition,embodiments of the disclosure may be practiced within a general purposecomputer or in any other circuits or systems.

Embodiments of the disclosure may be practiced via a SOC where each ormany of the element illustrated in FIG. 1 may be integrated onto asingle integrated circuit. Such a SOC device may include one or moreprocessing units, graphics units, communications units, systemvirtualization units and various application functionality all of whichmay be integrated (or “burned”) onto the chip substrate as a singleintegrated circuit. When operating via a SOC, the functionalitydescribed herein with respect to embodiments of the disclosure, may beperformed via application-specific logic integrated with othercomponents of computing device 400 on the single integrated circuit(chip).

Embodiments of the present disclosure, for example, are described abovewith reference to block diagrams and/or operational illustrations ofmethods, systems, and computer program products according to embodimentsof the disclosure. The functions/acts noted in the blocks may occur outof the order as shown in any flowchart. For example, two blocks shown insuccession may in fact be executed substantially concurrently or theblocks may sometimes be executed in the reverse order, depending uponthe functionality/acts involved.

While the specification includes examples, the disclosure's scope isindicated by the following claims. Furthermore, while the specificationhas been described in language specific to structural features and/ormethodological acts, the claims are not limited to the features or actsdescribed above. Rather, the specific features and acts described aboveare disclosed as example for embodiments of the disclosure.

What is claimed is:
 1. A method comprising: receiving a set of two ormore base phase vectors; measuring, by an Access Point (AP) in anetwork, a measured phase vector for a first signal from a user device;determining projection values based on a comparison of the measuredphase vector to each base phase vector; determining subset of base phasevectors with the highest projection values; and sending the projectionvalues and the subset of base phase vectors to a location server,wherein the location server determines a location of the user devicefrom the projection values and the subset of base phase vectors.
 2. Themethod of claim 1, wherein the subset of base phase vectors is one basephase vector.
 3. The method of claim 1, wherein each base phase vectoris associated with a heat map.
 4. The method of claim 3, wherein, ifthere are more than one base phase vector in the subset, combining theheat maps associated with each base phase vector.
 5. The method of claim4, wherein the projection values for the subset of base phase vectorsdetermine a weight of the heat map.
 6. The method of claim 5, whereinthe two or more base phase vectors are each at a different angle.
 7. Themethod of claim 6, wherein the two or more base phase vectors areorthogonal to each other.
 8. The method of claim 1, further comprising:receiving an Received Signal Strength Indicator (RSSI) threshold fromthe location server; determining a RSSI value for the first signal fromthe user device; comparing the determined RSSI value to the RSSIthreshold; and if the determined RSSI value is above the RSSI threshold,providing location information about the user device to the locationserver.
 9. The method of claim 8, wherein if the determined RSSI valueis not above the RSSI threshold, the AP: providing the locationinformation and the determined RSSI value about the signal from the userdevice to the location server; or not providing location information tothe location server.
 10. The method of claim 9, wherein if thedetermined RSSI value is above the RSSI threshold, the user device is ona same floor as the AP.
 11. A system comprising: a network; a firstAccess Point (AP) in communication over the network, the first APcomprising: a first memory storage; a first processing unit coupled tothe first memory storage, wherein the processing unit is operative to:receive an Received Signal Strength Indicator (RSSI) RSSI threshold froma location server; receive a set of two or more base phase vectors;receive data corresponding to a first signal from a user device; basedon receiving the data corresponding to the first signal, determine anRSSI value for the first signal; compare the determined RSSI value tothe RSSI threshold; if the determined RSSI value is above the RSSIthreshold: measure a measured phase vector for the first signal;determine projection values based on a comparison of the measured phasevector to each base phase vector; determine subset of base phase vectorswith the highest projection values; and send the projection values andthe subset of base phase vectors to the location server in a secondsignal.
 12. The system of claim 11, wherein the two or more base phasevectors are each at a different angle, and wherein the two or more basephase vectors are orthogonal to each other.
 13. A system comprising: anetwork; a first Access Point (AP) in communication over the network,the first AP comprising: a first memory storage; a first processing unitcoupled to the first memory storage, wherein the processing unit isoperative to: receive an RSSI threshold from a location server; receivea set of two or more base phase vectors; receive data corresponding to afirst signal from a user device; based on receiving the datacorresponding to the first signal, determine an Received Signal StrengthIndicator (RSSI) value for the first signal; compare the determined RSSIvalue to the RSSI threshold; if the determined RSSI value is above theRSSI threshold: measure a measured phase vector for the first signal;determine projection values based on a comparison of the measured phasevector to each base phase vector; determine subset of base phase vectorswith the highest projection values; send the projection values and thesubset of base phase vectors to the location server in a second signal;the location server in communication with the AP over the network, thelocation server comprising: a second memory storage; a second processingunit coupled to the second memory storage, wherein the second processingunit is operative to: receive location information and RSSI informationfrom the first AP associated with a location of the user device; basedon the RSSI information, generate the RSSI threshold; send the RSSIthreshold to the first AP; receive a set of projection values and basephase vectors from the first AP; and based on the projection values andthe base phase vectors, generate a combined heat map that indicates thelocation of the user device.